What is Molecule in Chemistry ?

Updated on Jan. 8, 2021 03:20 PM IST by Lakshmi Arya


  1. A group having two or more atoms that are chemically bonded together is called a molecule.
  2. A molecule is the smallest particle of an element or a compound that is capable of an independent existence and shows all the properties of that substance.

Molecules of Elements:-  
The molecule of an element are constitute by the same type of atoms. Such Molecules are called Homoatomic Molecules. For example,a molecule of oxygen consists of two atoms of oxygen (O2) and if 3 atoms of oxygen combine into a molecule ,we get ozone (O3).
The number of atoms present in a molecule of an element is called it's atomicity.
Molecules of argon (Ar),helium(He)etc. are made up of only one atom of that element and hence they are called monoatomic.
Oxygen, hydrogen, nitrogen and chlorine are diatomic molecule.
Some elements have 3,4or more atoms of that element and hence are called triatomic, tetra-atomic and polyatomic respectively.

Molecules of Compounds:-
Atoms of different elements join together in definite proportions to form molecules of Compounds. Such Molecules are called Hetroatomic Molecules. For example two atoms of hydrogen and one atom of oxygen combine to make one molecule of water.

Total Views: 969

Related FAQs

Q. what is an ion ? Give an example.

Ans: An ion is a charged particle (positive or negative) formed by an atom or a group of atoms.Common salt is chemically sodium chloride (NaCl). It's constituting particles are positively charged sodium io... read more

Q. What is atomicity ? Calculate the atomicity of CuSO4, HCl, PbNO3, S8, NaCl, H2CO3, N2O

Ans: The total number of atoms present in a molecule of an element, compound or matter is known as the atomicity. Atomicity of CuSO4= 6 (one atom of copper,one atom of sulphur, four atoms of oxygen) Atomic... read more

Q. How many atoms are present in a H2S molecule and CO molecule?

Ans: In H2S molecule there are three atoms(2 Atoms of hydrogen and 1 atom of sulphur) In CO molecule there are two atoms (1atom of carbon and one atom of Oxygen).... read more

Q. Write difference between H2 and 2H.

Ans: H2 is a molecule form by the combination of two H atoms whereas 2H is two hydrogen atoms.... read more

Q. What are ionic and molecular compounds? Give examples.

Ans: The compounds formed by transfer of electron from metal to non metal to gain inert gas configuration is known as ionic compound. Example: sodium chloride, potassium chloride etc. The compounds form... read more